The present invention is related to prosthetic heart valve replacement, and more particularly to devices, systems, and methods for animal testing of prosthetic heart valves.
Prosthetic heart valves that are collapsible to a relatively small circumferential size can be delivered into a patient less invasively than valves that are not collapsible. For example, a collapsible valve may be delivered into a patient via a tube-like delivery apparatus such as a catheter, a trocar, a laparoscopic instrument, or the like. This collapsibility can avoid the need for a more invasive procedure such as full open-chest, open-heart surgery.
Collapsible prosthetic heart valves typically take the form of a valve structure mounted on a stent. There are two types of stents on which the valves structures are ordinarily mounted: a self-expanding stent and a balloon-expandable stent. To place such valves into a delivery apparatus and ultimately into a patient, the valve must first be collapsed or crimped to reduce its circumferential size.
When a collapsed prosthetic valve has reached the desired implant site in the patient (e.g., at or near the annulus of the patient's heart valve that is to be replaced by the prosthetic valve), the prosthetic valve can be deployed or released from the delivery apparatus and re-expanded to full operating size. For balloon-expandable valves, this generally involves releasing the entire valve, assuring its proper location, and then expanding a balloon positioned within the valve stent. For self-expanding valves, on the other hand, the stent automatically begins to expand as the sheath covering the valve is withdrawn. Once a self-expanding valve has been fully deployed, it expands to a diameter larger than that of the sheath that previously contained the valve in the collapsed condition.
Designs of prosthetic heart valves may be tested in large animals before the designs are used in human patients. Typically, aortic valves are tested in healthy animals that do not have calcific aortic valve stenosis. Such healthy animal aortas may be less resistant to radial expansion than a diseased human aorta, which may result in prosthetic heart valves migrating away from the installed location in a healthy animal aorta.
There therefore is a need for improvements to the devices, systems, and methods for animal testing of prosthetic heart valves. Among other advantages, the present invention may address one or more of these needs.